Mercerville, New Jersey has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 44.9 °F (low) to 64 °F (high). Annual precipitation averages 47.9 Inches. Mercerville is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 24.1 °F | 40.5 °F | 3.53 in. |
| February | 25.5 °F | 43.1 °F | 2.67 in. |
| March | 32.4 °F | 51.0 °F | 4.34 in. |
| April | 42.4 °F | 63.0 °F | 3.56 in. |
| May | 52.1 °F | 72.6 °F | 4.05 in. |
| June | 61.3 °F | 81.7 °F | 4.49 in. |
| July | 66.7 °F | 86.3 °F | 5.05 in. |
| August | 65.0 °F | 84.6 °F | 4.52 in. |
| September | 57.8 °F | 78.2 °F | 4.07 in. |
| October | 46.2 °F | 66.2 °F | 3.92 in. |
| November | 36.2 °F | 55.6 °F | 3.34 in. |
| December | 28.9 °F | 45.3 °F | 4.32 in. |
| Annual | 44.9 °F | 64 °F | 47.86 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |